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PubMed1992

A block in full-length transcript maturation in cells nonpermissive for B19 parvovirus.

Vertebrate parvoviruses share a similar genomic organization, with the capsid proteins encoded by genes on the right side and nonstructural proteins encoded by genes on the left side. The temporal and cell-specific appearances of these two types of gene products are regulated by a variety of genetic mechanisms. Rodent parvovirus structural proteins, for example, are encoded by a separate promoter which is positively regulated by nonstructural-gene products. In contrast, for the human B19 parvovirus, the analogous structural-gene promoter is nonfunctional, and both left- and right-side transcripts originate from a single promoter and are highly processed. Using a combination of sensitive RNA analyses of wild-type and mutant templates, we have found that the relative abundance of these alternatively processed transcripts appears to be governed by unique postinitiation events. In permissive cells, the steady-state level of right-side structural-gene transcripts predominates over that of left-side nonstructural-gene transcripts. In nonpermissive cells transfected with the B19 virus genome, nonstructural-gene transcripts predominate. Removal of 3' processing signals located in the middle of the viral genome increases transcription of the far right side. Disruption of a polyadenylation signal in this region makes readthrough of full-length right-side transcripts possible. These results suggest that the abundance of B19 virus RNAs is determined by active 3' processing and is coupled to DNA template replication.

Animals↗
PubMed1993

Interconnection between thyroid hormone signalling pathways and parvovirus cytotoxic functions.

Nonstructural (NS) proteins of autonomous parvoviruses can repress expression driven by heterologous promoters, an activity which thus far has not been separated from their cytotoxic effects. It is shown here that, in transient transfection assays, the NS-1 protein of the parvovirus minute virus of mice (MVMp) activates the promoter of the human c-erbA1 gene, encoding the thyroid hormone (T3) receptor alpha. The endogenous c-erbA1 promoter is also a target for induction upon MVMp infection. Moreover, T3 was found to up-modulate the level of cell sensitivity to parvovirus attack. These data suggest an interconnection between T3 signalling and NS cytotoxic pathways.

Animals↗
PubMed1995

Characterization of mouse parvovirus infection by in situ hybridization.

Infection of young adult BALB/cByJ mice with mouse parvovirus-1, a newly recognized, lymphocytotropic, nonpathogenic parvovirus, was examined by in situ hybridization. Virus appeared to enter through the small intestine and was disseminated to the liver and lymphoid tissues. Strand-specific probes detected virion DNA in a consistently larger number of cells than replicative forms of viral DNA and/or viral mRNA. The number of signal-positive cells in the intestinal mucosa, lymph nodes, spleen, and thymus increased through day 10 after oral inoculation but decreased after seroconversion. Positive cells were still detected, however, in peripheral lymphoid tissues of mice examined at 9 weeks postinoculation. The results underscore the need to assess potential effects of persistent mouse parvovirus-1 infection on immune function in mice.

Animals↗
PubMed1996

Parvovirus minute virus of mice strain i multiplication and pathogenesis in the newborn mouse brain are restricted to proliferative areas and to migratory cerebellar young neurons.

Newborn BALB/c mice intranasally inoculated at birth with a lethal dose of the immunosuppressive strain of the parvovirus minute virus of mice (MVMi) developed motor disabilities and intention tremors with a high incidence by the day 6 postinfection (dpi). These neurological syndromes paralleled the synthesis of virus intermediate DNA replicative forms and yield of infectious particles in the brain, with kinetics that peaked by this time. The preferred virus replicative sites in the brain were established early in the infection (2 dpi) and at the onset of clinical symptoms (6 dpi) and were compared with major regions of cellular proliferative activity found after intraperitoneal injection of bromodeoxyuridine 24 h before encephalons were subjected to immunohistochemistry detection. At 2 dpi, viral capsid antigen was located in the laterodorsal thalamic and the pontine nuclei but not in the extensive proliferative regions of the mouse brain at this postnatal day. At 6 dpi, however, the neurotropism of the MVMi was highlighted by its ability to target the subventricular zone of the ventricles, the subependymal zone of the olfactory bulb, and the dentate gyrus of the hippocampus, which are the three main germinal centers of the cerebrum in mouse postbirth neurogenesis. Unexpectedly, in the cerebellum, the MVMi capsid antigen was confined exclusively to cells that have undergone mitosis and have migrated to the internal granular layer (IGL) and not to the proliferative external granular layer (EGL), which was stained with antiproliferative cell nuclear antigen antibody and is the main target in other parvovirus infections. This result implies temporal or differentiation coupling between MVMi cycle and neuroblast morphogenesis, since proliferative granules of the EGL should primarily be infected but must migrate in a virus carrier state into the IGL in order to express the capsid proteins. During migration, many cells undergo destruction, accounting for the marked hypocellularity specifically found in the IGL and the irregular alignment of Purkinje cell bodies, both consistent histopathological hallmarks of animals developing cerebellar symptoms. We conclude that MVMi impairs postmitotic neuronal migration occurring in the first postnatal week, when, through the natural respiratory route of infection, the virus titer peaks in the encephalon. The results illustrate the intimate connection between MVMi neuropathogenesis and mouse brain morphogenetic stage, underscoring the potential of parvoviruses as markers of host developmental programs.

Animals↗
PubMed1997

The cytotoxicity of the parvovirus minute virus of mice nonstructural protein NS1 is related to changes in the synthesis and phosphorylation of cell proteins.

Autonomous parvoviruses exert lytic and cytostatic effects believed to contribute to their antineoplastic activity. Studies with inducible clones have demonstrated a direct involvement of parvovirus nonstructural proteins (NS) in oncolysis. Human and rat fibroblasts have been stably transfected with MVM(p) (minute virus of mice prototype strain) NS genes cloned under the control of a hormone-inducible promoter. Dexamethasone-induced synthesis of the NS proteins in sensitive transformed cells results in cell killing within a few days. From these sensitive cell lines have been isolated some NS-resistant clones that also prove resistant to MVM(p) infection, suggesting that cell factors modulate NS cytotoxicity. We have previously reported that factors involved in cell cycle regulation may contribute to this modulation, since NS toxicity requires cell proliferation and correlates with a cell cycle perturbation leading to an arrest in phase S/G2. In addition to its role in cytotoxicity, NS1 can regulate transcription driven by parvovirus and nonparvovirus promoters. Since phosphorylation is a critical event in controlling the activity of many proteins, notably transcription factors and cell cycle-regulated proteins, we have examined the effect of NS1 on the synthesis and phosphorylation of cell proteins. Our results indicate that NS1 interferes, within 7 h of induction, with phosphorylation of a protein of about 14 kDa (p14). Cell synchronization has enabled us to show that phosphorylation of this protein occurs in early S phase and is prevented when NS1 is induced. This early effect of NS1 on p14 phosphorylation may be directly linked to cytotoxicity and is probably related to the previously reported inhibition of cell DNA synthesis. Late in the induction period (24 h), NS1 also alters the synthesis of a 50-kDa protein and a 35-kDa protein (p50 and p35, respectively). Microsequencing of p35 reveals sequence homology with beta-tubulin. These effects of NS1, observed only in NS1-sensitive cell lines, may be related to the protein's cytotoxicity.

Amino Acid Sequence↗
PubMed1999

Nuclear export factor CRM1 interacts with nonstructural proteins NS2 from parvovirus minute virus of mice.

The nonstructural NS2 proteins of autonomous parvoviruses are known to act in a host cell-dependent manner and to play a role in viral DNA replication, efficient translation of viral mRNA, and/or encapsidation. Their exact function during the parvovirus life cycle remains, however, still obscure. We report here the characterization of the interaction with the NS2 proteins from the parvovirus minute virus of mice (MVM) and rat as well as mouse homologues of the human CRM1 protein, a member of the importin-beta family recently identified as an essential nuclear export factor. Using the two-hybrid system, we could detect the interaction between the carboxy-terminal region of rat CRM1 and each of the three isoforms of NS2 (P [or major], Y [or minor], and L [or rare]). NS2 proteins were further shown to interact with the full-length CRM1 by coimmunoprecipitation experiments using extracts from both mouse and rat cell lines. Our data show that CRM1 preferentially binds to the nonphosphorylated isoforms of NS2. Moreover, we observed that the treatment of MVM-infected cells with leptomycin B, a drug that specifically inhibits the CRM1-dependent nuclear export pathway, leads to a drastic accumulation of NS2 proteins in the nucleus. Both NS2 interaction with CRM1 and nuclear accumulation upon leptomycin B treatment strongly suggest that these nonstructural viral proteins are actively exported out of the nuclei of infected cells via a CRM1-mediated nuclear export pathway.

Amino Acid Sequence↗
PubMed2002

Minute virus of mice NS1 interacts with the SMN protein, and they colocalize in novel nuclear bodies induced by parvovirus infection.

The human survival motor neuron (SMN) gene is the spinal muscular atrophy-determining gene, and a knockout of the murine Smn gene results in preembryonic lethality. Here we show that SMN can directly interact in vitro and in vivo with the large nonstructural protein NS1 of the autonomous parvovirus minute virus of mice (MVM), a protein essential for viral replication and a potent transcriptional activator. Typically, SMN localizes within nuclear Cajal bodies and diffusely in the cytoplasm. Following transient NS1expression, SMN and NS1 colocalize within Cajal bodies. At early time points following parvovirus infection, NS1 fails to colocalize with SMN within Cajal bodies; however, during the course of MVM infection, dramatic nuclear alterations occur. Formerly distinct nuclear bodies such as Cajal bodies, promyelocytic leukemia gene product (PML) oncogenic domains (PODs), speckles, and autonomous parvovirus-associated replication (APAR) bodies are seen aggregating at later points in infection. These newly formed large nuclear bodies (termed SMN-associated APAR bodies) are active sites of viral replication and viral capsid assembly. These results highlight the transient nature of nuclear bodies and their contents and identify a novel nuclear body formed during infection. Furthermore, simple transient expression of the viral nonstructural proteins is insufficient to induce this nuclear reorganization, suggesting that this event is induced specifically by a step in the viral infection process.

Animals↗
PubMed2004

Splice junction map of simian parvovirus transcripts.

The transcription map of simian parvovirus (SPV), an Erythrovirus similar to Parvovirus B19, was investigated. RNA was extracted from tissues of experimentally infected cynomolgus macaques and subjected to reverse transcription-PCR with SPV-specific primers. The PCR products were cloned and sequenced to identify splice junctions. A total of 14 distinct sequences were identified as putative partial transcripts. Of these, 13 were spliced; a single unspliced transcript putatively encoded NS1. Sequence analysis revealed that spliced partial transcripts may encode portions of open reading frames for the major capsid proteins VP1 and VP2 and smaller, unknown proteins. These unspliced and spliced transcripts and putative proteins encoded by SPV were similar to those of B19. Initial splice junctions at nucleotides 279 and 333 were analogous to those at nucleotides 406 and 441, respectively, in B19. Seven of the 10 splices identified had typical GT/AG donor/acceptor junctions. The splice sites were confirmed by Northern blotting and autoradiography. In contrast to B19, which has a maximum of two splices per transcript, up to three splices were observed in SPV transcripts. A spliced transcript putatively encoding a truncated version of NS1, as seen with minute virus of mice and adeno-associated virus 2, was also observed. The findings indicate that that the splicing pattern of transcripts of SPV and B19 is similar, but SPV also has coding strategies in common with other parvoviruses.

Animals↗
PubMed1984

Parvovirus infection in a family associated with aplastic crisis in an affected sibling pair with hereditary spherocytosis.

There have been many reports of aplastic crisis preceded by a febrile illness in hereditary haemolytic anaemias. Recent research has shown that the human parvovirus may be a causative agent. We report on an adult sibling pair with hereditary spherocytosis who presented in aplastic crisis after a febrile illness. Both had evidence of recent parvovirus infection, shown by the presence of IgM class specific antibody in their sera. The children of one of the sibling pair, one of whom has hereditary spherocytosis but no chronic haemolysis, showed similar evidence of acute parvovirus infection.

Adult↗
PubMed1989

Detection of parvovirus B19 DNA in fetal tissues by in situ hybridisation and polymerase chain reaction.

Attempts were made to detect human parvovirus B19-DNA by in situ hybridisation and the polymerase chain reaction in placental and fetal tissues from a case of intrauterine fetal death. In the in situ hybridisation experiments radioactive and non-radioactive (labelled with 2-acetyl-aminofluorene, AAF) DNA probes were used. B19-DNA was detectable in paraffin wax embedded fetal tissue from the liver, heart, lung, brain and thymus. The resolution with the AAF-labelled probes was higher than with the radiolabelled DNA. Parvovirus B19 DNA sequences were also detected in these tissues by an enzymatic in vitro amplification technique--the polymerase chain reaction. Amplification of a B19-DNA sequence before detection increases the rapidity and sensitivity of detection. The rapid, specific, and sensitive analysis of parvovirus B19 in normal and diseased tissues using these techniques may contribute considerably to determining the role of this virus as a risk factor in the outcome of pregnancy.

DNA Probes↗
PubMed1977

The effect on reproductive performance of porcine parvovirus infection in a susceptible pig herd.

An acute episode of reproductive failure occurred following natural introduction of porcine parvovirus to a susceptible herd of 48 breeding sows. Serological data gave a close estimate of the time that infection spread through the herd, and enabled a correct forecast of the reproductive failure that followed. Severe fetal mummification was seen over a three-week period. Epidemiological data is presented strongly linking in utero parvovirus infection with the mummification that occurred, and the significance of this data is discussed in connection with the present knowledge of transplacental porcine parvovirus infection.

Animals↗
PubMed1982

Canine parvovirus infection in housed raccoon dogs and foxes in Finland.

An outbreaks of severe enteritis occurred among young raccoon dogs on fur farms in eastern Finland. Post mortem examinations revealed gross and microscopic lesions which were typical of parvovirus infections described in cats, mink and dogs. The intestine was dilatated, oedematous and the normal villi were significantly reduced. A parvovirus was isolated from faeces and found to resemble canine parvovirus by its ability to haemagglutinate pig erythrocytes at pH 7.2 and its antigenic properties. Experimental inoculations showed that both housed raccoon dogs and foxes are susceptible.

Animals↗
PubMed1987

Maternally-derived antibodies to porcine parvovirus and their effect on active antibody production after vaccination with an inactivated oil-emulsion vaccine.

Two sows which had been vaccinated with an oil-emulsion porcine parvovirus vaccine, and had developed high haemagglutination-inhibiting antibody levels to the virus, farrowed three successive litters each, a total of 74 piglets. Serum samples from these piglets were tested for haemagglutination-inhibiting antibody at birth, three and 17 days after birth, and at monthly intervals thereafter to study the decline of maternally-derived antibody. Regression curves were constructed from the data to show the projected pathway (mean and 95 per cent tolerance limits) of the decline of maternally-derived antibody. Approximately half the pigs still had positive titres of up to 1/160 at six months old, and traces of antibody were detected in a few pigs at nine months. Thus, even at the onset of breeding some gilts can have maternally-derived antibody which may interfere with their ability to develop active immunity to porcine parvovirus. From the same litters three groups of 12 pigs were selected randomly and were vaccinated with a single dose of the oil-emulsion vaccine at 70 days, 130 days or 190 days respectively. Despite the presence of moderate to high titres of maternally-derived antibody, especially in the younger pigs, all of those vaccinated showed strong and long lasting antibody responses to the vaccine. High serum antibody titres at the time of vaccination seemed to depress the response to the vaccine slightly but the effect was not statistically significant. These results have important implications for prevention of reproductive failure induced by porcine parvovirus.

Animals↗
PubMed1988

Field trials of an inactivated, oil-emulsion porcine parvovirus vaccine in British pig herds.

Inactivated porcine parvovirus vaccines have been available commercially in Britain since 1984 and are now widely used in breeding herds. To investigate their value in cost benefit terms an oil-emulsion vaccine developed at Weybridge was used in trials on 1243 gilts in 12 herds during the period 1984 to 1986. In each herd approximately half the gilts were given the vaccine before breeding and the remainder were left unvaccinated. Blood samples were taken at vaccination and two to four weeks later to measure the serological responses, and the reproductive performances of the two groups were compared. When the data from all the gilts in the 12 herds were combined and analysed together there was surprisingly little difference between the reproductive performance of the vaccinated and unvaccinated groups. Only when the results from individual herds were analysed and interpreted against a background knowledge of wild parvovirus activity (as derived from a study of the serological results) did an understanding and evaluation of the benefits of vaccination become possible. As herds vary with respect to the absence or presence of porcine parvovirus and the epidemiology of the infection it is recommended that vaccination be used with discrimination; it should then prove highly cost effective.

Age Factors↗
PubMed1980

Canine parvoviral disease: experimental reproduction of the enteric form with a parvovirus isolated from a case of myocarditis.

Five 7-week-old pups and four 4-week-old pups, all seronegative to canine parvovirus, were inoculated intravenously with 1000 haemagglutinating units of canine parvovirus originally isolated from the myocardium of a dog with naturally occurring myocarditis. After three days, pups in both litters became pyrexic, anorectic and depressed, with vomiting and diarrhoea. The 4-week-old pups were killed on day 4, and the 7-week-old pups died or were killed on day 5 post-inoculation. Histological examination showed degeneration and necrosis of intestinal crypt epithelial cells and villous atrophy. All pups had thymic atrophy caused by lymphoid depletion. Peyer's patches, mesenteric lymph node and spleen also had lymphoid depletion. Lymphoid necrosis was present occasionally in these tissues. In the bone marrow, granulocytes and granulocyte and erythroid precursors were depleted. Amphophilic intranuclear inclusion bodies were abundant in crypt epithelial nuclei, less so in myocardial nuclei. Canine parvovirus was isolated from intestinal contents, thymus, spleen, mesenteric lymph node and liver in most pups, but not from kidney or myocardium.

Animals↗
PubMed2003

Intravenous immunoglobulin treatment of four patients with juvenile polyarticular arthritis associated with persistent parvovirus B19 infection and antiphospholipid antibodies.

Children with rheumatic oligoarthritis and polyarthritis frequently establish persistent parvovirus B19 infections that may be associated with the production of antiphospholipid antibodies (anti-PL IgG). In this study we analysed the influence of high-dose intravenous immunoglobulin (IVIG) therapy on virus load, on the level of anti-PL IgG and its potential capacity to improve the patients' clinical status. Four juvenile patients with long-lasting polyarticular rheumatic diseases and persistent parvovirus B19 infection, associated in three cases with the presence of antibodies against beta2-glycoprotein I (anti-beta2GPI IgG), were treated with two cycles of IVIG on five successive days (0.4 g/kg per day). Clinical parameters including scores of disease activity, virus load and anti-PL IgG levels were determined before, during and after treatment. Two patients showed a complete remission that has lasted 15 months. During that period they showed neither clinical nor laboratory signs of inflammation. Viral DNA was not detectable in serum, and a decrease in anti-beta2GPI IgG was observed. As assessed by the Childhood Health Assessment Questionnaire and the Health-related Quality of Life Questionnaire for Children, both patients were no longer restricted in their activities of daily living and no impact on the health-related quality of life was observed. In one patient the therapy failed: there was no improvement of symptoms and no decrease in virus load or inflammatory parameters. In the fourth patient, clinical and laboratory parameters did not improve despite a decrease in both viral load and anti-PL IgG. Our results show that the use of IVIG to treat parvovirus B19-triggered polyarticular rheumatic disease of childhood might offer an opportunity to improve this disabling condition.

Journal Article↗
PubMed1988

Virucidal efficacy of physico-chemical treatments against coronaviruses and parvoviruses of laboratory animals.

Virucidal efficacy of chemical disinfectants, heating and ultraviolet radiation against mouse hepatitis virus (MHV), canine coronavirus (CCV), Kilham rat virus (KRV) and canine parvovirus (CPV) were examined. Coronaviruses (MHV and CCV) were inactivated by ethanol, isopropanol, benzalkonium chloride, iodophor, sodium hypochlorite, sodium chlorite, cresol soap and formaldehyde as well as by heating at 60 degrees C for 15 minutes, whereas parvoviruses (KRV and CPV) appeared to be inactivated by disinfectants such as formaldehyde, iodophor, sodium hypochlorite and sodium chlorite. Parvoviruses were stable under heating of up to 80 degrees C for 30 minutes. Ultraviolet radiation inactivated all viruses within 15 minutes. No significant differences in stability against physico-chemical treatments were seen between viruses in the same group.

Animals↗
PubMedDate not supplied

[Transient pancytopenia induced by parvovirus B19 in a child with hereditary spherocytosis]

OBJECTIVE: To describe the occurrence of transient pancytopenia induced by parvovirus B19 infection in a patient with hereditary hemolytic anemia and to discuss the importance of the diagnosis of this pathology.METHODS: Case report of a child whose diagnosis was made by polymerase chain reaction (PCR) and serology, and review of the literature.CLINICAL REPORT: A twelve year-old male patient with hereditary spherocytosis, presenting non-specific symptoms of an infectious syndrome followed by severe and transient pancytopenia, whose diagnosis was a parvovirus B19 infection.CONCLUSION: The diagnosis of parvovirus infection has a particular importance in hematology, especially on some morbid conditions, among them the hereditary hemolytic anemias. PCR is useful because of its rapidness and sensitivity on the specific diagnosis of this disease.

Journal Article↗